Feed device



Aprilzs, 1944. N EUNN v2,347,271

FEED DEVICE Filed Dec. 50, A1939 I GA; VAroA Pmi-,3

- Patented Ape. 2s, 1944 Norman F. Linn, nooene, ruin. N. J., ossimor-`so Standard il Development Company, a corporation of DelawareApplication December 30,1939, Serial No. 311,831

3 Claims.

The present invention relates to an apparatus for feeding finely dividedpulverulent materials into a high pressure zone from a zone of lowerpressure. More particularly, the invention relates to a means fordischarging inely powdered catalyst materials into a cracking vessel ora feed line thereto, in which a gaseous material is contained under asubstantially higher pressure than that existing in the reservoir forthe powderedmaterial, or outside the line. Specifically, the inventionrelates to a pocket type feed mechanism providing for the more or lesscontinuous introduction of powdered catalyst under the circumstances setforth, and to the combination of such a mechanism with other elements ina complete system.

It is an object of the inventionto provide for the continuousintroduction of a powdered matethrough a restricted opening or slot 1 atthe end of the plate I. The powdered material from the hopper s carriedthrough the easing in the powdered material in the line ..but also toprerial into a zone of higher pressure without blow` back' or pressureloss, and also to prevent any packing or coking of the catalyst materialin the vicinity of the point of introduction.

These objects and` others inherent .in the structure and operation maybe fully understood from the following speciiication when it is readnetos a cylindrical member having about its Iperiphery a seriesof,helical pockets 2, cut in the face of the member I in such mannerthat one end of one pocket is disposed in spaced.

l slightlyoverlapping relation to the other end-of another, along a lineparallel' to the axis of said member. For the'purpose of thedescription. the cylindrical member I may be termed a feed wheel, thepockets 2 being formed or cut between spacing portions I. These angular.arcuate pockets 2 are preferably formed or out in the feed wheel at anangle of not more 30, with reference to the axis or a surface lineparallel thereto.

As shown in Fig. 2, a. feed wheel 1 is disposed within a casing 4thecasing opening upwardly .and exposing the feed wheel surface within ahopper or reservoir 5,- and opening downwardly into a zone of higherpressure, such as line t,

rf ci vent the 'reactive material from coming in contact with the powderbefore it leaves the feeding mechanism.'

Various means may accumulation of caked material on the surfaces 3 ofthe feed member I between the respective pockets 2, such as may becaused by pressure between the closely spaced surfaces of the feed wheeland casing. For example, the edge portion of the plate I may be heldagainstthegear under slight tension so as to act as a scraper to removeany particles adhering thereto'.l

Figs. 2 and 3 illustrate the simplest arrangement of elements accordingto the invention, the powdered material .being discharged directly fromthe reservoir therefor into the reaction zone inlet line. As shown inFig. 2, the discharge plate 8 is disposed diametrically opposite -tliehopper outlet. In the structure illustrated by Fig. 3, however,provision is made for balancing the pressure seal desired between thereaction zone or vessel inlet and the reservoir. In this arrangement,the plate l is disposed at a point about from the hopper outlet in thedirection of rotation of the feed wheel. When the pockets pockets areempty and the seal depends almost entirely upon the surface to surfacerelation between the case and feed wheel. a greater coni tact or sealingarea is desirable. The desired balance between the sealing areas' isobtained substantially in the manner shown,

The structure shown according to Fig.4 is `particularly suitable for usewhen the pressures existing in the reaction vessel, or adjacent thepoint at which the powdered material is to be introduced, areexceptionally high.v As illustrated, the feed wheel mechanism iscombined with a screw type feeder. In addition to the fact that thiscombination improves the seal obtained,

be utilized to prevent the it has been found that when thus combined,the constancy and uniformity of the feeding step is greatly improvedalso.

In the structure shown, powdered material is introduced into the line 9through line t, by

means of the feed member I. 'Ihe powdered material to be handled by thefeed wheel i is received by way of the line Il in which is disposed aconstant diameter screw feed member I2, the line il communicating with ahopper or reservoir i3. The screw feed member l2, while it may beconstant in pitch as well as diameter, is preferably of decreasingpitch, so that an increased sealing effect may be obtained. Therelatively large volumes of solids receivable in the 'rst few nights ofthe screw are compacted into the smaller volume of the'smaller flights,producing the desired result. Although a screw feed mem-- which the geari revolves. This form of structure is illustrated, and it has theadvantage of provid-l ing for the redispersion of the powdered materialdischarged from the screw member. aiding in avoiding-the formation oflumps of compressed material. That portion of the line il in which suchre-dispersion is to take place is indicated as chamber Ila. The screwmember and feed wheel when thus combined are intended to be rotated -bypower derived from the same source, their speeds f rotation andthereforetheir rates of delivery being adjusted to their respective capacities.

The structure as described is suitable for use in a variety ofoperations, but itis particularly adapted to combination in a processfor the cracking of hydrocarbon materials in the presence of a nelydivided or comminuted catalyst material such as activated clay. In sucha process, large volumes of catalyst must be supplied to the system in acontinuous fashion, and at a rate which by its uniformity wil1 maintainthe proper ratio between the volume of catalyst and the volume of thereactive materials. As disclosed, the apparatus contemplated provides ameans by which the feed rate of catalyst may be maintained within thedesired limits, while avoiding the eifects produced by escape orblow-back of portions of the reactive material into prematurecontactwith the catalyst material to cause coking and clogging of themechanisms and passages through K I c: y

l. In an apparatus for feeding powdered catalyst into a reaction zonefor the heat and pressure treatment of hydrocarbon material, a highpressure reaction zone adapted to contain the `hydrocarbon materialunder elevated temperai ture and pressure, a reservoir for the powderedcatalyst at lesser temperature and pressure, a conduit connecting thezone and reservoir, a feed wheel for positively feeding the catalystfrom the reservoir into the conduit toward the zone at a constant anduniform rate, the feed wheel comprising a cylindrical member withrelatively wide peripheral spacing portions between a series of helicalpockets, the spacing portions cooperating with the wall of the conduitto form a substantially fluid-tight t, and an inlet for fluid inert tothe hydrocarbons opening into the conduit between rthe wheel andreaction zone to iluidize the powdered catalyst on itsway to thereaction zone and prevent the hot hydrocarbon material from contactingthe catalyst before the catalyst leaves the feed wheel.

2. In an apparatus for feeding powdered catalyst into a reaction zoneforthe heat and pressure treatment of hydrocarbon material, a highpressure' reaction zone adapted to contain the hydrocarbon materialunder elevated temperature and pressure, a reservoir for the powderedcatalyst at lesser temperature and pressure, a conduit connecting thezone and reservoir, a feed wheel for positively feeding the catalystfrom the reservoir through the conduit toward the zone at a constant anduniform rate, and a compression screw member in the conduit between thereservoir and the feed wheel, the feed wheel comprising a cylindricalmember with relatively wide peripheral spacing portions between a seriesof helical pockets, the spacing portions cooperating with the wall o1'the conduit to form a substantially duid-tight fit'. f

3. In an apparatus for feeding powdered catalyst into a'reaction zonefor the heat and pressure treatment of hydrocarbon material, a highpressure reaction zone adapted to contain the hydrocarbon material underelevated temperature and pressure, a reservoir for the powdered catalystat wall of the conduit to form a substantially iiuidtightt, and an inletfor iluid inert to the hydrocarbons opening into the conduit between thewheel and reaction zone to iiuldize the powdered catalyst on its way tothe reaction zone and prevent the hot hydrocarbon material fromcontacting the catalyst before the catalyst leaves the feed wheel.

- NORMAN F. LlNN.

